Animals and other organisms obtain the energy available in carbohydrates through the process of cellular respiration.
When we say cellular respiration it is a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate (ATP), and then release waste products.
The relationship between these two is that cells take the carbohydrates into their cytoplasm, and through a complex series of metabolic processes, they break down the carbohydrates and release the energy (cellular energy).